The present disclosure relates to three dimensional (3D) printing, or additive manufacturing (AM), including continuous resin flow based mask video projection stereolithography (MVP-SLA).
Current AM, or 3D printing, techniques depend on accumulation of materials layer by layer. The fabrication speed is limited by the recoating speed (i.e., adding fresh resin for each layer). Hence the layer-based AM process may spend much of the time in waiting for the platform or tank movements during the building process. In current AM techniques utilizing a SLA, the resin filling process can take up much more than half of the fabrication time.
FIG. 1A shows an example of a mask image projection based MIP-SLA apparatus 100. Some existing AM processes employing MIP-SLA can be used to address speed limitations associated with typical laser based SLAs. A MIP-SLA 100 can be employed to fabricate a model using layer-by-layer additive techniques in a MIP-SLA process, for example. As an example illustrated in FIG. 1A, the apparatus 100 can use light, such as ultraviolet (UV) light, that is emitted from a light source 101 and then reflected by a Digital Micromirror Device (DMD) 102, to be transmitted through the lens 104 of an optical system and subsequently to the liquid resin surface 105. In some embodiments, the light source 101 can be implemented as a light emitting diode (LED). The MIP-SLA apparatus 100 can include a tank 110 that can be utilized as a large container to hold, or otherwise maintain, the liquid resin 106 and for keeping the liquid resin surface 105 leveled while stationary, for example. The focusing mask image provides sufficient energy to cure the portion of liquid resin 106 that is associated with the exposure into a solid. A portion of the liquid resin 106 can be solidified in the shape of a two-dimensional image projected by the DMD 102. The DMD 102 can be designed to include over a million mirrors, and thereby producing a projection mask image having relatively high resolution in speeds that are much faster in comparison to laser-based SLA technologies. After curing a thin layer of liquid resin 106 to fabricate a layer of the built physical model 107, which can be a 3D printed object for instance, the Z linear stage 108 can perform movement along a Z axis, namely in the vertical direction (e.g., move up or move down), to refresh the liquid resin 106 such that the resin for the next layer can be prepared. Additionally, a platform 111 can move, after a previous layer has been cured, in order to spread liquid resin 106 into a uniformly thin layer for recoating the next layer. In layer-based AM techniques the process can be repeated until the entire built physical model 107 is completely fabricated. The building of each layer may require a full cyclic motion including both moving the platform 111 up and down in the Z axis, and moving the tank 110 back and forth in the X axis.